Rapid amygdala gamma oscillations in response to eye gaze

Sato, W., Kochiyama, T., Uono, S., Matsuda, K., Usui, K., Inoue, Y., & Toichi, M.

他者の視線は，重要な社会的情報を伝え，複数の心理活動を喚起する．そうした活動のいくつか―情動反応や注意シフトなど―は，すばやく起こる．神経科学研究は，扁桃体がすばやい視線処理に関与することを示唆する．しかし，扁桃体の視線処理のスピードを特定する証拠はなかった．この問題を検討するため，我々はヒト深部脳波を計測した．被験者は，それたあるいはまっすぐな方向の，視線あるいはモザイクを観察した．扁桃体は，視線に対してモザイクよりも強いガンマ波活動を，方向に関わらず，ピーク潜時200msで示した．こうした結果は，ヒト扁桃体が，視線をすばやく処理することを示す．

PLoS One, 6, e28188

The eye gaze of other individuals conveys important social information and can trigger multiple psychological activities. Some of which, such as emotional reactions and attention orienting, occur very rapidly. Although some neuroscientific evidence has suggested that the amygdala may be involved in such rapid gaze processing, no evidence has been reported concerning the speed at which the amygdala responds to eye gaze. To investigate this issue, we recorded electrical activity within the amygdala of six subjects using intracranial electrodes. Subjects observed images of eyes and mosaics pointing in averted and straight directions. The amygdala showed higher gamma-band oscillations for eye gaze than for mosaics, which peaked at 200 ms regardless of the direction of the gaze. These results indicate that the human amygdala rapidly processes eye gaze.

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